1. Field of the Invention
The present invention relates to a polishing apparatus for optical fiber end surface for polishing the end surface of a ferrule used for an optical fiber connector of an optical-fiber communication circuit together with an optical fiber.
2. Description of the Related Art
To make an optical connection by physically contacting a ferrule with an optical fiber, it is preferable that a contact plane is polished into a flawless and spherical surface. Moreover, to improve the connection efficiency, it is desired that the physical spherical-surface contact keeps an angled physical contact (APC). In the case of an angled physical contact ferrule (APCF) requiring the slant spherical-surface polishing for performing polishing by slanting up to approx. 8.degree. to 12.degree. in relation to the optical axis of an optical fiber in order to decrease a return reflection loss, it is difficult to grind the ferrule end surface because the ferrule end surface is greatly removed due to polishing.
U.S. Pat. No. 4,831,784 discloses a polishing apparatus for optical fiber end surface for polishing the end surface of a ferrule together with an optical fiber by supporting a plurality of ferrules with optical fibers by one holder.
The present invention makes it possible to grind the distal ends of a ferrule and an optical fiber into a flawless surface by moving a holder in relation to a base along a small circle, that is, moving the distal end of the optical fiber along the small circle and rotating a polishing board in relation to the base and thereby, according to the relative movement between them.
In the case of U.S. Pat. No. 4,979,334, a plurality of optical fibers supported by a holder are spherically polished together with a ferrule by moving the center of a polishing board along a circle and rotating the board in relation to a base. The distal ends of the ferrule and the optical fiber are polished into a flawless surface.
U.S. Pat. No. 5,140,660 discloses a ferrule polishing apparatus and the polishing method. The ferrules are available for an angled physical contact (APC). In the apparatus, a polishing film is placed on an elastic pad on a polishing board.
The apparatuses disclosed in U.S. Pat. No. 4,831,784 and U.S. Pat. No. 4,979,334 realize considerably preferable polishing. However, fluctuation in qualities due to an inclination of a holder may occur between ferrules.
Therefore, to solve the above problem, U.S. Pat. No. 5,351,445 uses a linearly-guiding mechanism vertically moving on the outer circumference of the holder in parallel with a base so that the holder does not incline in the relative movement for polishing between the polishing board and the holder in U.S. Pat. No. 4,979,334.